Method for making cork sheet material



Aug. 9, 1938. A. WEISENBURG METHOD FOR MAKING CORK SHEET MATERIAL 4 Sheets-{Sheet 1 Filed Oct. 17, 193 1- Aug. 9, 1938.

A. WEISENBURG METHOD FOR MAKING CORK SHEET MATERIAL Filed Oct. 17, 1954 4 Shqets-Sheet 2 4 Sheets-Sheet 3 Aug. 9, 1938. A. WEISENB URG METHOD FOR MAKING CORK SHEET MATERIAL Filed Oct. 17, 1934 A. WEISENBURG 4 METHOD FOR MAKING CORK SHEET MATERIAL Aug. 9, 1938.

4 Shee ts-Sheet 4 Filed Oct. 17, 1954 Patented Aug. 9, 1938 UNITED STATES METHOD FOR MAKING CORK SHEET MATERIAL Andrew Weisenburg, Baltimore, Md., assignor to Crown Cork & Seal Company, Inc., Baltimore, Md, a corporation of New York Application October 1'7,

4 Claims.

The present invention relates to an improved method and apparatus for molding cork composition into a body and for forming continuous sheet material from such molded body. By cork com- 5 position, I mean comminuted cork and a binder of such character that the mass may be compressed into various shapes and the binder cured or set to form a solid body material suitable for fabrication into various articles. In the present instance, the cork composition is molded to a cylindrical form and the sheet material in required dimensions is severed therefrom.

As distinguished from previous methods of molding, the present invention embodies a method wherein the cork composition is formed or extruded into a hollow cylindrical body by the simultaneous application of both a rotary pressure and an axial pressure.

Briefly stated, by reason of the application simultaneously of axial and rotary pressure, the cork particles occupy a position in the hollow cylinder which is the resultant of these two forces. Such position, I have discovered, enables the cylinder to be sheeted into a uniform strong sheet free from weakened areas. An important feature of the method is the formation of the hollow cylindrical cork body by a continuous feed of the cork into a mold having an annular cavity, whereby the body is continuously and progressively built up in the mold while at the same time the body is maintained continuously under axial pressure.

Another feature of the method resides in maintaining the cork mass substantially free and uncompressed substantially until it is introduced into the mold cavity. This permits the particles to adapt themselves freely and more or less indepentently of one another to the mold, as distinguished from the introduction of a substantially preformed mass, whereby a body of substantially uniform density is produced.

The method further embodies the cutting or severing of the cork composition from the cylinder in a continuous sheet by a tangential cutting,

4.3 e. g., by rotating the cylinder of cork composition past a cutting blade disposed tangential to the cylinder, or vice versa. I find that by reason of the positioning of the, particles as explained and the tangential cutting of the 5- sheet, that the bond between the particles is not injured or destroyed. This is important for the reason that the cork predominates .by volume and constitutes the body mass, and any undue pressure exerted upon the cork composition to Which would ve d i d. h bo d between 1934, Serial No. 748,713

the cork particles or to break it, would render the sheet weak and useless for practical purposes.

Thereafter such sheet is severed by a down-. ward pressure, i. e., punching or cutting, to form various shaped articles, such as bottle cap liners, gaskets, and similar products. These articles will be characterized by enhanced tensile strength in all directions, because the severing of the sheet from a cylinder having the cork particles positioned as explained is accomplished with substantially none or a minimum of strain and without distending or destroying the bond between the cork particles.

The invention also comprises a machine whereby the cork composition cylinder will be ex truded or formed by means of a rotary and axial pressure and in a single operation. The apparatus includes means for continuously exerting endwise or axial pressure at both ends of the cork cylinder simultaneously with the packing and extrusion of the cork composition. The cylinder is produced upon a core whereby it can be removed from the molding or extrusion apparatus and subsequently passed through an oven or other means to cure. the binder and thereafter positioned upon the sheet severing machine.

In connection with the machine, moreover, the means for imparting rotary and axial pressure during packing and extrusion, consists of a novel screw arrangement whereby not only is the proper rotary pressure exerted but of equal importance, the distribution of the binder coated cork particles is such that a cylinder of uniform density is produced. 'An important feature of the machine from the standpoint of producing a cylinder of uniform .density is that the com struction and arrangement of the parts permits the introduction into the mold cavity of substantially free and uncompressed cork as distinguished from substantiallycompressed or preformed cork strips or ribbons. This permits the particles to be uniformly distributed throughout the body and to produce a body substantially uniformin its density throughout.

Other objects and advantages of the invention will become apparent from thefollowing description when taken in conjunction with the accompanying claims and drawings.

Referring to the drawings, wherein is disclosed a preferred embodiment ofthe apparatus for carrying out my method:

. Figure 1 is a front view of the feeding and packing machine, withthe mold removed from the platform; V

Figure 2 is a central cross section of'Figure 1 showing the platform and mold in their elevated positions;

Figure 3 is a sectional view taken substantially along the line 3-3 of Figure 1;

Figure 4 is an enlarged detail axial sectional view of the mold and its associated parts;

Figure 5 is a side view of the outer cylinder of the mold.

Figure 6 is a sectonal view taken substantially along the line 6-6 of Figure 5;

Figure '7 is a view showing the sequence of steps employed in forming a continuous strip of material from a cylindrical body in accordance with my invention;

Figure 8 is a composite plan view of a sheet of material showing an article such as an automotive gasket and cap liner formed therefrom.

Figure 9 is a view showing a conventional cork composition block, the vertical arrows indicating the direction of the pressure and the horizontal arrow the direction of cutting into sheets.

Figure 10 is a view showing a conventional cork composition cylinder formed by the action of a reciprocating plunger or packer working in i a tube, the arrows indicating the direction of the pressure,

Figure 11 is a view of the cylinder of Figure 10, the arrows showing tangential application of a cutting force to such a cylinder for forming sheets which I have discovered produces a weakened sheet.

The method and apparatus of the present invention are particularly concerned with the manufacture ofa cork composition, which in sheeted form and the article produced therefrom exhibits enhanced tensile strength and freedom from brittleness. These are important considerations in the manufacture of bottle cap liners and gaskets which of necessity are subjected to high sealing pressures.

Apparatus Referring to the drawings, a supporting frame Ill comprising vertically extending spaced bars or members II and cross bars I2 connected to the same, is employed. This frame may be set on the floor or a suitable base I3.

Carried by the frame is a movable or sliding platform I4 shown in detail in Figure 3. Referring to Figures 1 and '3, this platform has extending from its sides pairs of spaced guides I5. Carried by the vertical frame members II are guide rods I6 fixed to the frame by means of suitable brackets I6. These guide rods I6 are freely received in the guides I5 of the sliding platform I4 and constitute a guiding and centering means therefor.

The movable platform I4 is connected to a reciprocating piston rod I1 carrying a piston working in a cylinder I8, and this connection is (a) through a cross head I9 rigidly connected by a nut 28 to one end of piston rod I1 and reciprocated therewith whereby the cross head is movable with the piston rod, and (b) by means of a pair of sprocket chains 2I each connected as at one end 2 I to one end of the cross head I9 and working over sprocket wheels 22-23; the opposite ends of chains 2I are connected as at to suitable rods 25 carried by the guide brackets I5 of platform H. In this manner, movement of the piston rod I1 will move the platform I4, and likewise movement of the platform will act to move the piston rod and its piston against the pres sure in cylinder I8.

Referring to Figure 3, the platform I4 has a plurality of spaced upwardly extending centering pins 21, which are adapted to engage and center a cylindrical and open ended mold member 28, detachably carried by the platform I4. The platform I4 is also provided with a central boss 29 and an offset locking pin 38, which engage openings in one end or bottom 32 of a closed tubular core 3I, to center the core and hold it against rotation on the platform. As will be observed, the outer mold member 28 and the core 3| are mounted on the platform I4 and hence are movable therewith. Said mold member and core' as shown are detachable from the platform and form between them an annular mold cavity. Carried by the frame I0 is a tubular member or shell 33 fixed to the frame by means of a bracket 34 connected to frame members II as at 34 and shown in Figure 2. Positioned within the shell 33 is a revoluble drum or feeder 35 which is rotated and supported by a drive shaft 36 which is operatively connected to pulley 31 through gearing 38. The pulley is operated in any desired manner to rotate the drum or feeder 35.

The mold members 28 and 3I carried by platform I4 cooperate with the fixed shell 33 and rotatable drum 35. Referring to Figure 4, it will be noted that these several parts are slidably nested i. e., the shell 33 fits within the mold member 28 and the core 3| of the mold fits Within the rotatable drum 35. The purpose of this construction will be later described. Referring to Figure 5, the outer cylinder 28 of the mold is preferably formed of the sections 48 and 4| provided with laterally disposed tapered bosses 42 which, when brought together, form a tapered pin 43 arranged to receive a locking member 44 having a complementary tapered opening 45 for maintaining the sections 40 and M in their closed positions. This construction allows these sections to be readily opened for removing the molded material after the latter is formed. The outer surface of the cylindrical member 28 may be provided with spaced strengthening bands 46.

The granulated binder coated cork is introduced into the machine from hopper 41 as shown in Figure l, and with the mold members 28 and 3|, and the shell 33 and rotatable drum 35, in the nested position shown in Figures 1 and 4. In such relation, the annular plate or disc I4, detachably mounted on the platform I4, closes the space at the bottom between the members 28 and 3|. The platform and members 28 and 3| carried thereby are supported in this position by reason of the retraction of the piston rod in the cylinder under the pressure exerted upon the piston therein. That is, the pressure in thecylinder I 8 is such that the piston rod I! is moved downwardly whereby the platform I4, shell 28 and core 3| are moved upwardly so that the tubular members nest and the plate [4' forms a closed bottom for the nested members working against the pressure in cylinder I8.

The rotatable drum 35 I have heretofore mentioned as a feeder and in this connection, referring to Figure 2, it will be noted that at its lower end the drum has a pair of separate blades 48 and 49. These blades extend spirally from opposite sides of the drum, forming a double blade feed, one convolution beginning and ending on one side of the diameter and the other convolution beginning and ending on the opposite side of the diameter. This double convoluted feed screw of the structure recited not only constitutes an efficient, feed, but, of equal importance, exerts a positive rotary and axial pressure and assures thorough distribution of the binder coated cork to form a cylindrical object of uniform density. As will be observed (Figures 2 and 4), each screw extends for only a single convolution around the drum 35, with the result that there is no appreciable friction between the cork and the wall of the shell 33 as the cork is propelled by the screw and thus there is no substantial preforming or. compression of the cork before it is introduced into the annular cavity of the mold beneath the screw. The short formation of this screw is of particular importance since it permits the introduction into the mold cavity of substantially free and uncompressed cork.

I With the parts in the position shown in Fgures 1 and 4, the granulated cork is continuously fed from the hopper 41 and enters the spaces defined by the shell 33 and the rotatable drum 35. The granular mass gravitates as a substantially free uncompressed mass into engagement with the rotating blades 48 and 49 on the drum 35, and these blades pack the binder coated comminuted cork between the mold 28 and core 3| against the plate I4 removably positioned on the platform I l. The pressure in the cylinder I8 is regulated and as the packing continues, the platform and mold members 28 and 3| are moved downwardly away from the fixed shell 33 and drum 35 as shown in Figure 2 without disturbing the feed passage defined by the inner and outer members, and until the material builds up on the platform to substantially the height of the mold and core. This packing, it will be noted, takes place against the packing pressure exerted on one side of the platform and the fluid pressure obtained in the cylinder exerted on the opposite side of the platform. As will be understood, the pressure exerted by the spiral convolutions on the feed drum 35 and by the platform is only upon the cork in the mold cavity since the cork above the spirals 48, 39 is free and uncompressed. Thus there is maintained upon the cork as the cylindrical body is progressively and continuously formed, a continuous endwise or axial pressure which is not transmitted to the cork above the body in the mold cavity due to the fact that the spirals completely fill the space between the drum 35 and the shell 33 (Figure 2). The short single convolution of each spiral avoids any appreciable packing or compression 'of the cork within the spirals since it travels only a short distance and there is no such friction created between the cork and the walls of the shell 33 as would cause a packing or compression of the cork in the spirals. In operation, the initial pressure in the cylinder I8 will be such as to move the platform It to bring this member into engagement with the lower end of the shell member 33. The pressure in the cylinder is then increased to a predetermined amount and regulated as required in order to yieldably oppose the downward pressure exerted on the mold and platform during the packing operation to obtain a cork composition cylinder of desired density. The granulated cork and binder are introduced into the mold, and rotary movement imparted to the drum 35 through the gearing 38 and pulley 31. The downward feeding and packing pressure exerted by the double blades 43 and 39 packs the material into the mold and as this pressure is greater than the set pressure in the cylinder I8, the platform l4, together with the cylinder member 28 and core 3|, are gradually moved away from the fixed member 33 until the cylinder body is completely formed, at which time the upper end of the member 28 is spaced from the opposed lower end of the member 33 so as to permit the convenient removal of the mold from the platform. During this operation, the core 3| is prevented from turning, due to the locking engagement of the pin 30 with the bottom of the core.

The screw comprising blades 4849 exerts continuously a rotary and axial packing pressure whereby the cork is extruded and packed to build up a cylinder of uniform density, the density factor being controlled by the pressure in cylinder l8.

The screw, moreover, imparts a simultaneous axial and rotary pressure on the cork so that the granules are oriented to lie in a path which is the resultant of these two forces.

As the extrusion and packing continues, the cylinder of cork composition is built up to substantially the height of the members 28 and 3| whereupon the extruding and packing and cork feed operation is discontinued. In this position of the parts, the members 28 and 3| are free of the shell 33 and drum 35, i. e., below the same, and are removed from the machine with the ring l4 closing one end of the space between the members 28 and 3|. A cover ring I4 is now applied to the opposite end of the members 28 and 3| as shown in Figure 5, so that both ends are closed. The machine is then ready for a contiunation of the operations described.

The floor l3 may have a well or recess for receiving and supporting the cylinder l8. Any suitable fluid such as air, water, or oil may be used to actuate the piston and piston rod I1, and the flow of the fluid supply to the cylinder is preferably controlled by a valve 5|.

Method By reference to the preceding description, it will be observed that the cork composition is extruded and packed by a simultaneous rotary and downward axial pressure. The cork is continuously fed into the annular mold cavity by the rotating drum 35 from the free uncompressed body of cork in the shell33 above the spiral feed blades 48 and 4.9. Thus the hollow cylindrical core body is continuously and progressively formed and the cork as introduced into the mold cavity is substantially free and uncompressed, the individual cork particles being thus permitted to move more or less independently into the proper positions and produce a body having uniform density.

During the continuous formation of the hollow cylindrical cork body there is maintained on the latter a continuous endwise or axial pressure resulting from the continuous feed of the blades 68, 49 at one end and the upward pressure on the platform l8 at the other end of the body. The method is particularly useful in the formation of a hollow cylindrical body as distinguished from a solid rod since it permits the subsequent tangential cutting of the sheets from cylindrical sections having relatively long radii as distinguished from relatively small rod sections. Moreover, by the method described there is no central section of small diameter which is not adaptable for tangen tial slicing and which would therefore be wasted.

There results a cork composition cylinder wherein the cork particles are arranged or oriented to occupy a position which is the resultant of these forces, which resultant is substantially along radial lines.

After the cylinder is formed and removed from the machine and the cover plate l4 applied, and referring to Figure 7, it is transferred to a continuous type oven 52 and passed therethrough to cure or set the binder. Thereupon, the sectional mold member 28 and bottom and top ring members M are removed and there remains the core 3| having a cork composition cylinder 53 thereon.

This cylinder and core are mounted on a cutting machine having a travelling cutter blade 54 in the form of an endless band moving longitudinally with respect to the cylinder 53 continuously over suitable pulleys and having its cutting edge disposed tangentially as shown at 56 to the cylinder. The cylinder and core are rotated as shown by the arrows 6! on a suitable shaft 55 of the cutting machine which engages the core 3| and simultaneously the tangentially disposed cutting blade engages the cylinder, the blade moving in the direction indicated by the arrow 62. In this manner, the cork composition is severed into a a continuous. sheet of required thickness which may be wound on a roll 55 if desired, and in which event the rotation of the cylinder and core, and the roll 58, respectively, is accomplished in synchronism. Either the cutting blade or the shaft 55 is moved progressively toward one or the other as each layer is removed from the cylinder 53 in order to constantly maintain the cylinder and cutter in cutting relation.

I have discovered that by forming the cork composition cylinder through the medium of a downward axial and rotary pressure such tangential cutting into sheets may be availed of to form a uniform sheet of high tensile strength. The cork particles, as stated, are oriented to have a position which is the resultant of the two forces and which force resultant lies along substantially radial lines. Hence, the application of a tangential cutting force as explained will be at substantially right angles to the radial line pressure employed in forming the cylinder. It is this feature of the present invention which enables the formation of cork composition sheets in the manner described, possessing remarkably strong characteristics and free from weakened areas.

In Figure 9, I have illustrated a block of cork composition formed conventionally in a suitable square mold and wherein the cork composition is subjected to, i. e., compressed by, a downward or vertical pressure as indicated by the vertical arrows. The severing of this block into sheets is accomplished at right angles to this downward molding pressure as shown by the horizontal arrow. Such sheets have a tensile strength which is sufficiently strong to make the cork composition practically useful.

Referring to Figures and 11, I have illustrated a cork composition cylinder formed conventionally by a simple downward reciprocating pressure, i. e., the cork composition is compressed in a tube by a reciprocating plunger or packer. Such a cylinder, when subjected to a tangential cutting for the purpose of forming cork composition sheets, results in a sheet which is weak and has little or no utility. This appears due to the fact that the cutting is not accomplished at right angles to the packing pressure, with the result that the cork particles are strained and the bond between them is ruptured.

The present invention, however, utilizes as the packing force, two components, namely, an axial pressure and a rotary pressure, and the cork particles are positioned in accordance with the resultant of these two forces. As stated, this resultant is substantially along radial lines, and when the cylinder is subjected to a tangential cutting, as described, the cutting force acts at substantially right angles to the radial resultant force. In this manner, a highly desirable sheet of required thickness and tensile strength is obtained.

In Figure 8 I have shown the sheet 51 and an automotive gasket 59 and a cap liner Bil punched or cut therefrom.

The cork composition employed comprises a body mass of comminuted cork, i. e., the cork predominates by volume and the granules are coated with a binder which may be of any suitable type.

It will therefore be seen that, by reason of my improved method and apparatus, the cylindrical body for forming sheet material may be economically and expeditiously produced at a minimum expenditure of time and labor, while the formed sheet and articles made therefrom will have inincreased tensile strength in the directions subjected to the greatest strains.

It is understood that the improved method and apparatus herein disclosed are merely illustrative of preferred embodiments and that such changes as fall within the purview of one skilled in the art may be made without departing from the spirit of the invention and the scope of the appended claims.

I claim:-

1. The method of producing cork sheet material which comprises forming from loose binder-coated cork particles a hollow cylindrical body by continuously feeding the cork into a mold having an annular cavity and thereby continuously and progressively forming the cylindrical body, continuously maintaining the body under axial pressure while it is being formed, curing the binder, and then cutting the body tangentially to its outer periphery to form a sheet.

2. The method of producing cork sheet material which comprises forming from loose binder-coated cork particles a hollow cylindrical body by con tinuously feeding the cork into a mold having an annular cavity and thereby continuously and progressively forming the cylindrical body, continuously maintaining the body under axial pressure while it is being formed, maintaining the cork substantially free and uncompressed substantially until it is introduced into its position in the mold cavity, curing the binder, and then cutting the body tangentially to its outer periphery to form a sheet.

3. The method of producing a cork body for use in the manufacture of cork sheet material which comprises forming from loose binder-coated cork particles a hollow cylindrical body by continuously feeding the cork into a mold having an annular cavity with a closed bottom and side walls, continuously and progressively building the cylindrical body within the mold until the latter is substantially filled, and continuously maintaining the body under axial pressure while it is being built.

4. The method of producing a cork body for use in the manufacture of cork sheet material which comprises forming from loose binder-coated cork particles a hollow cylindrical body by continuously feeding the cork into a mold having an annular cavity with a closed bottom and side walls, continuously and progressively building the cylindrical body within the mold until the latter is substantially filled, continuously maintaining the body under axial pressure while it is being built, and maintaining the cork substantially free and uncompressed substantially until it is introduced into its position in the mold cavity.

ANDREW WEISENBURG. 

